The present disclosure is related to biomedical optical imaging methods. More particularly, the present disclosure is related to the noninvasive photoacoustic imaging of tissue vasculature.
The vascular network of the circulatory system is an essential part of living organisms, providing a function that is responsible for transport of nutrients and oxygen to cells and removal of waste products. Blood hemoglobin confined to blood vessels serves as the oxygen carrier and has vital importance for tissue health, healing and cell growth across the human body.
Noninvasive imaging of tissue vasculature may provide important information about the health of an organism, disease development and response to specific therapy administered during treatment procedures. The laser photoacoustic method of vascular imaging relies on optically induced pressure waves in tissue to visualize the position and oxygen content of blood hemoglobin taking advantage of the unique spectral signatures of oxy- and deoxy-hemoglobin. In principle, two- and three-dimensional photoacoustic imaging can be accomplished using a single element ultrasonic transducer mechanically scanned over the region of interest. Unfortunately, this imaging modality is notoriously slow and tedious. Furthermore, the use of large pulsed laser sources operating at slow repetition rates (˜10 Hz) makes it difficult or impossible to design and construct portable clinical field imaging photoacoustic systems operating at real-time image formation rates.